Endurance, suffering toenail rot (10)
I believe the answer is:
toleration
'endurance' is the definition.
(thesaurus)
'suffering toenail rot' is the wordplay.
'suffering' indicates an anagram.
'toenail'+'rot'='toenailrot'
'toenailrot' with letters rearranged gives 'TOLERATION'.
(Other definitions for toleration that I've seen before include "Allowance of what is not approved" , "Patience" , "liberalism" , "Indulgence" , "liberality" .)